I was writing MONDAY on the chalkboard in bold, bubbly letters, when he sank to the bottom of the pool. He stayed down there so long I decided to join him. He was impressed that I, too, could defy gravity and ruminate at the bottom. When I came up for air I found my friend and placed a nautilus in her hand. She asked me if I was a teacher and I said, Right. But not as a question, as a conviction.